Heater



FIG. 1 is a front view of a heater showing my new design;

FIG. 2 is a rear view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a perspective view thereof.

The broken line showing of the handle is for the purpose of illustrating environmental structure and forms no part of the claimed design.

In FIG. 2, the broken lines depict environmental subject matter only and form no part of the claimed design. 

The ornamental design for a heater, as shown and described. 